Glass insulating panel

ABSTRACT

A glass panel includes a first glass substrate, a second glass substrate, a spacer profile at the periphery of the glass panel between the first and the second glass substrate. There is an intermediate substrate in the intermediate space between the first and the second glass substrates, the substrate having a first coefficient of thermal expansion, and means to maintain the intermediate substrate within the intermediate space. The panel also includes a second profile, having a second coefficient of thermal expansion, positioned facing the inner face of the spacer profile within the intermediate space between the first and second glass substrates of the glass panel. The second profile carries the means to maintain the intermediate substrate within the intermediate space. A difference between the first coefficient of thermal expansion and the second coefficient of thermal expansion is less than or equal to 20%.

FIELD OF THE INVENTION

This invention relates to glass panels, and to methods of manufacturingthe same.

DESCRIPTION OF THE RELATED ART

Glass panels are used in multiple applications such as windows, doors,transparent walls, shelves, show cases for instance in a building andalso in vehicles.

A certain type of glass panels that can be particularly interesting forits insulating properties are the multiple glass panels. Such panelscomprise several sheet of glass separated by gas filled intermediatespace, a spacer profile at the periphery of the glass panel being usedto maintain the intermediate spaces between the sheets of glass and aseal (commonly made of butyl) being used to seal the intermediatespaces. The most common multiple glass panels being the double glasspanels or double glazings.

Among the glass panels, for instance, the glass lighting panels withintegrated light sources such as light emitting diodes (LEDs), areknown, e. g. for displaying information, for decoration or for lightingpurposes. For these application areas, the manufacturing of a glasspanel with electronic components typically comprises the steps ofdepositing a conductive layer on a first glass substrate, realization ofelectronic circuits in the conductive layer and depositing of electroniccomponents on the conductive layer, connected to the electroniccircuits. In the case of a laminated glass panel, a plastics interlayeris then deposited on the conductive layer and a sandwich is obtained bythe application of a second glass substrate on the plastics interlayer,which is then laminated as outlined before. In the case of an insulatingglass panel, a second glass substrate is maintained, thanks to a spacerprofile deposited at the periphery of the first glass substrate, at adistance from the first glass substrate so as to form an intermediatespace between the first and second glass substrates.

In each of these applications it is necessary to furnish an electricsupply to the conducting layer for supplying electrical power to theLEDs. EP 1 840 449 describes such a panels of glass embedding LEDs. TheLEDs are arranged in a regular grid at 5 cm intervals such that thearray of diodes covers substantially the entire area of glazing panel.Each LED has a surface area of about 4 mm². First and second bus barsextend substantially along the entire length of one edge of the panelbetween the two glass sheets.

It is also known to use light sources such as light emitting diodes(LEDs) that are arranged to emit light into laminated glass panels alonga plane of the panel such as described in WO2010097110A1. In thatdocument, the LEDs are arranged to emit light into the plasticinterlayer that is at least partially light diffusive to cause the lightto be deflected which causes the glass panel to be illuminated.

It is also known to use LEDs that are arranged to emit light intomultiple glazings panels along a plane of the panel such as described inUS20080184636A1.

Lighting panels comprising at least one organic glass layer with LEDsthat are arranged to emit light into the organic glass layer such asPlexiglas EndLighten sold by EVONIK Industries are also known. In suchpanel, the organic glass layer is made of Poly(methyl methacrylate)embedding colorless diffuser particles which cause the light to diffuseforwards.

Most of the time, the periphery of the glass panels are embedded in aframe that is used to hide the periphery of the panel (comprising forinstance the spacer profile and the seal) but also to attach the glasspanel to the part of the building or structure that shall receive it.

The fixation of the frame to the building or structure can be done forexample thanks a seal (mortar) material that fills the space between theframe and the surfaces of an opening in which the panel should beintegrated or thanks to screws, thanks to glues, Nevertheless, when apanel comprising multiple sheets of glass (organic and/or inorganic)and/or plastics and/or other materials is fixed in a vertical positiondepending of the material (and more particularly for more flexiblematerials), the sheet has to have a minimum width (for example 8 mm fora sheet of Plexiglas EndLighten of 1 m×1 m dimensions) in order to avoidbuckling. This can be a concern in particular when the weight or thecost (that is closely related to the width of the substrate) of thepanel needs to be reduced.

SUMMARY OF THE INVENTION

According to a first aspect, the invention provides a glass panel,comprising:

-   -   a first glass substrate,    -   a second glass substrate,    -   a spacer profile at the periphery of the glass panel between the        first and the second glass substrate, the spacer being used to        maintain an intermediate space between the first and second        glass substrates, the spacer profile having an outer surface and        an inner surface,    -   an intermediate substrate in the intermediate space between the        first and the second glass substrates,    -   means to maintain the intermediate substrate within the        intermediate space.

According to present invention, the panel comprises further a secondprofile (100), having a second coefficient of thermal expansion,positioned facing the inner face of the spacer profile (103) within theintermediate space (104) between the first (101) and second (102) glasssubstrates of the glass panel (1), the said second profile (100)carrying on the means (108) to maintain the intermediate substrate (105)within the intermediate space (104), and wherein the difference betweenthe first coefficient of thermal expansion of the intermediate substrate(105) and the second coefficient of thermal expansion of the secondprofile (100) is lower or equal to 20%.

Using a second profile to maintain the intermediate substrate within theintermediate space, the second profile having the same coefficient ofthermal expansion than the coefficient of thermal expansion of theintermediate substrate allows to reduce the stress between the secondprofile and the intermediate substrate in the intermediate space betweenthe first and the second glass substrates.

Embodiments of the invention can have any other features added, somesuch additional features are set out in dependent claims and describedin more detail below.

According to an aspect of the invention, the panel is disposed in avertical position and the means to suspend the intermediate substratecomprises means to attach a upper portion of the intermediate substrateto a upper portion of the second profile.

Therefore, thanks to the fact that the intermediate substrate may besuspended in the intermediate space, when the panel is arranged in thevertical position, buckling of the intermediate substrate is preventedwhatever the width of the intermediate substrate. Then, smaller widthintermediate substrate can be used in order to reduce the weight or costof the panel.

It is understood in the present invention that the term “outer surfaceof the spacer profile” means the surface in contact with the environmentoutside the glass panel and the term “inner surface of the spacerprofile” means the surface in contact with the intermediate spacebetween the first and second glass substrates of the glass panel.

To avoid any doubt, the term “coefficient of thermal expansion” and itsabbreviation “CTE” will be used equally in the present invention.

According to the present invention, said second profile comprises meansto maintain the intermediate substrate in the intermediate space betweenthe first and the second glass substrates.

According to an embodiment of the present invention, said attachmentmeans consist in:

-   -   at least one first opening in said upper portion of the second        profile,    -   at least one second opening in the lower portion of the second        profile, the first and the second openings being disposed in        regard,    -   the at least first and second opening being designed to lodge at        least a portion of the edges of the intermediate substrate.

According to a preferred embodiment of the present invention, theintermediate substrate is preferably fixed to the internal faces of thefirst and second openings provided in the second spacer profile.

According to a preferred embodiment of the present invention, at least aportion of the edges (upper and lower) of the intermediate substrate ofthe intermediate substrate inserted into corresponding first and secondopenings are glued to the internal faces of the first and secondopenings provided in the second spacer profile in order to well fix theintermediate substrate to the second pacer profile to avoid any movementof the intermediate substrate.

According to an aspect of the invention, the intermediate substrate isan intermediate organic glass substrate.

According to an aspect of the invention, the panel comprises at leastone light source.

According to an aspect of the invention, the second profile comprisesmeans to lodge the at least one light source so as the at least onelight source emits light into the intermediate organic glass substratepredominantly along a plane of the panel.

According to an aspect of the invention, at least part of theintermediate organic glass substrate is arranged to deflect the lightout of the plane of the panel and through at least one of the first andsecond glass substrates to provide a diffused light output.

By using a second profile to suspend the intermediate substrate withinthe intermediate space having the same coefficient of thermal expansionthan the coefficient of thermal expansion of the intermediate substrateand at least one light source to emit light into the intermediateorganic glass substrate allows:

-   -   to reduce the stress between the second profile and the an        intermediate substrate in the intermediate space between the        first and the second glass substrates,    -   to maintain a set distance between the at least one light source        and intermediate substrate.

Thus, a glass panel with an improved esthetic with a better diffusion ofthe light emitted form at least one light source and lifetime isproposed by the present invention.

Also, by having the light deflected by the organic glass substrate, itcan be spread or diffused more widely to reduce problems caused by moredirect illumination from point sources.

By having the intermediate organic glass substrate arranged between afirst and a second glass substrates, the organic glass substrate is thenprotected against any risk of the occurrence of defects such asscratches and/or stripes on its surface. And then local refraction ofthe light beam propagating through defects in the panel are avoided.Then, the uniformity of the light generated at the surface of panel andthe overall aesthetics of the illuminated panel are improved or arekept.

In the following, the expression default encompasses all kind of surfacedefault such as scratches, stripes, protrusion, roughness, striates,projections, slits, puncture, groove, depression, . . . The defects canbe microscopic. The defects can be macroscopic.

According to another aspect of the invention, the spacer profile and/orthe second profile also comprises means to dissipate heat generated bythe at least one light source.

According to another aspect of the invention, the means to dissipateheat comprise a heat sink embedded in the spacer.

Then, by having means to dissipate heat embedded in the spacer, theinvention allows for a better dissipation of heat generated by the lightsource(s) and then allows to embed in the panel higher densities oflight sources and/or higher power light source(s). As a matter of fact,for a good and efficient functioning of most of the light sources (suchas LEDs for instance), temperature in the environment around the lightsources shall be controlled to be inferior to a temperature threshold(above which the light source intensity or efficiency starts todecrease). Most of the light sources generate heat when functioning dueto their electric powering. The higher the electrical power supplied tothe light source, the more heat is generated. Moreover, the higher thedensity of light sources in an environment, the more heat is generatedin that environment. As a matter of fact, preliminary tests have shownthat, in such glass lighting panel where the light sources are LEDs, theambient temperature of the LEDs can be up to 60° C., which greatlyreduces their lifetime. Therefore, the heat dissipating means are veryimportant particularly when high light output is required.

A solution to limit/avoid the temperature increase due to electricalpowering of the light sources is to dissipate generated heat.

According to another aspect of the invention, the means to lodge atleast one light source is a profile embedded into the second profilebetween the first and the second glass substrates so as to face an edgeof the intermediate organic glass substrate.

According to another aspect of the invention, the profile embedded inthe second profile to lodge at least one light source has a inversedU-shape and the at least one light source is placed on the profile toface an edge of the intermediate organic glass substrate. Preferably,the profile is a metallic profile and more preferably the profile is analuminum profile.

According to another aspect of the invention, the intermediate organicglass substrate is at least partially light diffusive to cause the lightto be deflected.

According to another aspect of the invention, the intermediate organicglass substrate is a Poly(methyl methacrylate) layer.

According to another aspect of the invention, the intermediate organicglass substrate is a Poly(methyl methacrylate) layer embedding colorlessdiffuser particles which cause the light to diffuse forwards.

Another aspect provides a second profile positioned facing the innerface of the spacer profile within the intermediate space between thefirst and second glass substrates of the glass lighting panel,comprising:

-   -   means to maintain an intermediate substrate in the intermediate        space between the first and the second glass substrates and    -   means to lodge at least one light source so as the at least one        light source is arranged to emit light into the intermediate        substrate predominantly along a plane of the panel.

According to another aspect of the invention, the second profile mayalso comprises means to dissipate heat.

According to another aspect of the invention, the means to dissipateheat comprise a heat sink embedded in the profile.

Another aspect provides a method of manufacturing a glass lighting panelcomprising a first glass substrate and a second glass substrate,comprising the following step:

-   -   providing a spacer profile at the periphery of the glass panel        between the first and the second glass substrate to maintain an        intermediate space between the first and second glass        substrates, the spacer profile having an outer and an inner        surfaces.

According to an aspect of the invention, the method also comprises thefollowing steps:

-   -   maintaining, thanks to a second profile, an intermediate organic        glass substrate in the intermediate space between the first and        the second glass substrates, the difference of CTE between the        CTE of the intermediate organic glass substrate and the CTE of        the second profile is lower or equal to 20%,    -   lodging, thanks to the second profile, at least one light source        so as the at least one light source emits light into the        intermediate organic glass substrate predominantly along a plane        of the panel,    -   arranging at least part of the intermediate organic glass        substrate to deflect the light out of the plane of the panel and        through at least one of the first and second glass substrates to        provide a diffused light output.

Any of the additional features can be combined together and combinedwith any of the aspects. Other advantages will be apparent to thoseskilled in the art, especially over other prior art. Numerous variationsand modifications can be made without departing from the claims of thepresent invention. Therefore, it should be clearly understood that theform of the present invention is illustrative only and is not intendedto limit the scope of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

How the present invention may be put into effect will now be describedby way of example with reference to the appended drawings, in which:

FIG. 1 shows a cross section view a portion of a panel according to aparticular embodiment according to which the light sources are LEDs thatare arranged at the periphery of the glass panel in the second profilein order to emit light in a direction along the plane of the glasssubstrates.

FIG. 2 illustrates the main steps of a method of manufacturing of theglass lighting panel of FIG. 1.

DESCRIPTOIN OF THE PREFERRED EMBODIEMNTS

The present invention will be described with respect to particularembodiments and with reference to certain drawings but the invention isnot limited thereto but only by the claims. The drawings described areonly schematic and are non-limiting. In the drawings, the size of someof the elements may be exaggerated and not drawn on scale forillustrative purposes.

Furthermore, the terms first, second, third and the like in thedescription and in the claims, are used for distinguishing betweensimilar elements and not necessarily for describing a sequential orchronological order. It is to be understood that the terms so used areinterchangeable under appropriate circumstances and that the embodimentsof the invention described herein are capable of operation in othersequences than described or illustrated herein.

Moreover, the terms top, bottom, over, under and the like in thedescription and the claims are used for descriptive purposes and notnecessarily for describing relative positions. It is to be understoodthat the terms so used are interchangeable under appropriatecircumstances and that the embodiments of the invention described hereinare capable of operation in other orientations than described orillustrated herein.

Similarly it should be appreciated that in the description of exemplaryembodiments of the invention, various features of the invention aresometimes grouped together in a single embodiment, figure, ordescription thereof for the purpose of streamlining the disclosure andaiding in the understanding of one or more of the various inventiveaspects. This method of disclosure, however, is not to be interpreted asreflecting an intention that the claimed invention requires morefeatures than are expressly recited in each claim. Rather, as thefollowing claims reflect, inventive aspects lie in less than allfeatures of a single foregoing disclosed embodiment. Thus, the claimsfollowing the detailed description are hereby expressly incorporatedinto this detailed description, with each claim standing on its own as aseparate embodiment of this invention.

Furthermore, while some embodiments described herein include some butnot other features included in other embodiments, combinations offeatures of different embodiments are meant to be within the scope ofthe invention, and form different embodiments, as would be understood bythose in the art. For example, in the following claims, any of theclaimed embodiments can be used in any combination.

In the description provided herein, numerous specific details are setforth. However, it is understood that embodiments of the invention maybe practiced without these specific details. In other instances,well-known methods, structures and techniques have not been shown indetail in order not to obscure an understanding of this description.

The invention will now be described by a detailed description of severalembodiments of the invention. It is clear that other embodiments of theinvention can be configured according to the knowledge of personsskilled in the art without departing from the technical teaching of theinvention, the invention being limited only by the terms of the appendedclaims.

Some of the features described below arise from an appreciation thatpanel comprising at least two sheets of glass embedding an intermediatesubstrate e.g. made of inorganic glass and/or plastics and/or othermaterials is fixed in a vertical position depending of the material (andmore particularly for more flexible materials), the intermediatesubstrate has to have a minimum width in order to avoid buckling. Thiscan be a concern in particular when the weight of the panel needs to bereduced.

Thus an objective of at least some of the embodiments is to provide apanel of glass comprising an intermediate substrate in which theintermediate substrate can have any and all widths without buckling ofthe intermediate substrate.

Thus an objective of at least some of the embodiments is to provide apanel of glass comprising an intermediate substrate the weight of whichcan be reduced.

Some other of the features described below arise from an appreciationthat the surfaces of an organic glass substrate are highly sensitive todefects such as scratches and/or stripes and/or protrusions and then, ifdefault are present on the surface of such a substrate, light generatedon the surface of such a substrate is not perfectly uniform and theoverall aesthetics of the panel is decreased.

Thus an objective of at least some of the embodiments is to provide apanel of glass including at least one light source which providessurface lighting with an improved uniformity. Another objective of someembodiments is to provide such a surface lighting panel in which theaesthetics of the panel is improved. Another objective of at least someembodiments is to provide such a surface lighting panel which allows toembed in the panel higher densities of light sources and/or higher powerlight source(s).

Some embodiments involve a glass lighting panel, comprising a firstglass substrate, an intermediate organic glass substrate, having a firstcoefficient of thermal expansion, a second glass substrate, a spacerprofile at the periphery of the glass panel between the first and thesecond glass substrates, and a second profile being used to maintain anintermediate space between the first and the second glass substrate,having a second CTE, the difference between the first of theintermediate organic glass substrate and the second CTE of the secondprofile is lower or equal to 20%. The glass substrates can encompassglass equivalents such as hard plastic or Perspex acrylic orpolycarbonate materials. The panel can have at least one light sourcelodged in the second profile so as to emit light into the intermediateorganic glass substrate predominantly along a plane of the panel.

The organic glass layer can be arranged to be at least partially lightdiffusive such that light emitted by the at least one light source isdeflected out of the plane of the panel and through the surfaces of atleast one of the glass substrates. This can be made partially diffusiveby choice of properties of the material, by adding particles (e.g.colorless or colored diffuser particles), by adding any kind ofreflective or partially reflective structures, or by surface treatmentsto hinder total internal reflection and so on. The panel according tothe invention can be flat and be for instance a building window or door,a partition wall for indoor or outdoor architectural applications, adisplay panel (e.g. for advertising), a road sign, . . .

Nevertheless, the panel does not need to be flat, it can be formed tohave a curved main surface for instance, the panel can be a vehicleglazing.

Some additional features of some of the embodiments are as follows.

In some cases at least one light source such as an LED, OLED etc. can beembedded in the second profile (in lodging means of the second profile)provided between the spacer profile and the intermediate space betweenthe first and the second panes of glass, in order to emit light into theintermediate organic glass substrate (preferentially at the edge of theintermediate organic glass substrate) in a direction predominantlyincluded in the plane of the panel.

According to a first aspect of the invention, only one light source canbe lodged in the second profile in order to emit light into theintermediate organic glass substrate. It can be lodged everywhere in thesecond profile and emit light in every portion of the edges of theintermediate organic glass substrate.

According to a preferred aspect of the present invention, the at leastone light source is provided on a profile embedded into the secondprofile/

Clearly according to other aspects of the invention, two, three, four,or any other quantity of light sources can be lodged everywhere in thesecond profile having the same CTE than the intermediate organic glasssubstrate so as to emit light into the intermediate organic glasssubstrate. In case of a perpendicular panel comprising a perpendicularintermediate organic glass substrate comprising four edges, the lightsources can be lodged in the second profile so as to emit in any portionof any edge of the intermediate organic glass substrate. The lightsources can also be lodged in the spacer on a regular basis so as toemit light on a regular basis in the four edges of the intermediateorganic glass substrate.

Any kind of light source that can be embedded in the second profilehaving the same CTE than the intermediate organic glass substrate can beimplemented in the present invention such as LED, OLED, laser diodes,fluorescent tube, fluorescent lamp, . . .

According to the present invention, an opening is provided in the secondprofile in the place where the at least one light source is disposed inorder to allow the light emitted from the at least one light source tobe diffused into the intermediate organic substrate.

FIG. 1 shows a portion of a cross section view of a glass lighting panel1 according to a particular embodiment of the invention.

The glass lighting panel 1 comprises a first glass plate or substrate(or sheet) 101, an intermediate substrate 105 that is for example anintermediate organic glass substrate 105 having a first CTE, a secondglass plate or substrate (or sheet) 102, a plurality of LEDs 106, aspacer profile 103 at the periphery of the glass panel 1 between thefirst 101 and the second 102 glass substrates to maintain theintermediate space 104 (or cavity) between the first and the secondglass substrates , and a second profile 100 having a second CTE, thedifference between the first and the second CTE is lower or equal to20%, the second profile 100 being used to maintain the intermediatesubstrate 105 in the intermediate space 104 (or cavity) between thefirst and the second glass substrates.

Preferentially, the second profile 100 comprises

-   -   means 107 to maintain the intermediate organic glass substrate        105 in the intermediate space 104, and    -   means 108 to lodge the LEDs 106 so that they emit light into the        intermediate organic glass substrate 105 predominantly along a        plane of the panel.

Preferentially, the means 108 to maintain the intermediate organic glasssubstrate 105 in the intermediate space 104 is an opening 1071 extendingalong at least a portion of the length of the intermediate organic glasssubstrate 105, the opening being arranged to lodge at least a bottomportion 1051 of the edges of the intermediate organic glass substrate105.

More preferably, the means 108 to maintain the intermediate organicglass substrate 105 in the intermediate space 104 further comprises anopening 1072 extending along at least a portion of the length of theintermediate organic glass substrate 105, the opening being arranged tolodge at least a upper portion 1052 of the edges of the intermediateorganic glass substrate 105, the first and the second openings 1071,1072 being disposed in regard.

Preferentially, the means 108 is a metallic inversed U-shape profileembedded into the second profile 100 on which LEDs 106, (potentially ina housing for each LED 106) are arranged so as to face an edge 1051 ofthe intermediate organic glass substrate 105.

Preferably the second profile 100 can be made from any suitable materialsuch as plastic or other material provided that the second profile 100has the same CTE than the intermediate organic glass substrate 105.

The second profile 100 can be made from the same material or a differentmaterial than the intermediate organic glass substrate 105 provided thatthey have the same CTE.

The spacer profile 103 can be made from any suitable material such asalumina, stainless steel, plastic, and many other materials.

According to the present invention, the spacer profile 103 alsocomprises means to dissipate heat generated by the LEDs 106.Preferentially, the means to dissipate heat comprise a heat sinkembedded in the spacer (not shown). Preferentially, the spacer profileis made from a heat conducting material such as a metal (e.g. alumina,stainless steel, . . . or combination thereof) or and the heat sink ismade by realizing wings on the edge of the spacer profile 103 that is incontact with the external atmosphere (external edge of the spacer).

Preferentially, the panel comprises means to maintain the intermediateinorganic glass substrate 105 within the intermediate space 104.

Preferentially, the panel is disposed in a vertical position (forexample it is the case when the panel is used as a window, or a door, ora separation wall or a vertical part of a show case, . . . ) and themeans to suspend the intermediate inorganic glass substrate 105comprises means to attach a upper portion 1052 of the intermediatesubstrate 105 to a portion 1032 of the second profile 100.

For instance, if the intermediate inorganic glass substrate 105 isrectangular and therefore comprises an upper 1052, two lateral edges1051 and a bottom portion 1051.

Preferentially, the intermediate organic substrate 105 is fixed to theopening 1071 thanks to any suitable piece (such as a thanks to two nutsthat are screwed to both threaded parts of the stem that exceed fromboth said first and second wings) or more preferably a material such asglue or is inserted under pressure (or pressed) in the opening.

Preferentially, at the level of the two lateral parts and a bottom partof the spacer profile 103, the means 107 to maintain the intermediatesubstrate 105 in the intermediate space 104 are just used to guide theintermediate substrate 105 and let a certain degree of liberty in allthe directions. It can be obtained by choosing a spacing between thefirst and the second glass plates 101 102 that is higher than the widthof the second profile 100.

On FIG. 1, the second profile is represented as having a rectangularsection, obviously, for better heat dissipation performances, the spacercan have a more bulky rectangular section. A metallic profile reversedU-shape profile 108 is embedded in the second profile 100. The LEDs 106are placed on the base of the U-profile 111 facing the intermediateorganic substrate 105.

The metallic profile 108 allows particularly to bring near the at leastone source of light 106 to the intermediate organic substrate 105 and tosupport also the at least one source of light 106.

According to the present particular embodiment, each LED 106 is lodgedin a housing 108 of the spacer profile on a regular basis so as to emitlight on a regular basis in the four edges of the intermediate organicglass substrate 105. For instance, the LEDs 106 are provided as aflexible adhesive strip, for instance, a LED strip sold by OSRAM withthe reference LF06P-W4F-854 or VISTAR VFS-N3528-120W-L1, in order to beglued (e.g. with an adhesive tape) in the housing 108 of the secondprofile 102 and more particularly on the means 108. The means 108 ismore preferably a metallic profile with a inversed U-shape.

According to the present particular embodiment, the glass lighting panel1 is an rectangular insulating multiple glazing panel embedding arectangular intermediate organic glass substrate. The intermediate spaceor cavity 104 can be filled with a gas such as air or any insulatinggas, e.g. Argon, Krypton, Xenon, SF6, CO2, . . . or any combination ofthe previously mentioned gas. A sealant, e.g. a butyl coating, can beprovided between the spacer and the internal surface (surface of thesubstrate that is in contact with the intermediate space 104) of thefirst and second glass substrate to seal the panel and avoid the gas toleave the cavity 104. Alternatively, a vacuum can be created in theintermediate space or cavity 104. Preferentially, the spacer profile 103is filled with or contain desiccant to remove moisture trapped in thegas space during manufacturing of the panel 1.

In order to supply power to the LEDs, for instance, a hole is drilled inthe edge of the spacer profile 103 and the second profile 102 throughthe means 108 and a cable is inserted through a protective tubularshaped polymer material. This tube protects the cable from the edges ofthe drilled (sharp) alumina. The cable is then soldered on adequateconnection pad(s) of the flexible adhesive LED strip. At least part ofthe intermediate organic glass substrate 105 is arranged to deflect thelight out of the plane of the panel and through at least one of thefirst and second glass substrates to provide a diffused light output.Preferentially, it is at least partially light diffusive to cause thelight to be deflected.

For instance, the organic glass substrate is a Poly(methyl methacrylate)layer and more particularly a Poly(methyl methacrylate) (hereafterreferenced PMMA) layer embedding colorless diffuser particles whichcause the light to diffuse forwards. For instance, the organic glasssubstrate has a width that is comprised between 2 mm to 10 mm or evenlower. Such thin organic glass substrates can be used due to the factthat said substrate is maintained and potentially suspended and then nobuckling occurs. For instance, the organic glass layer is a layer ofPlexiglas Endlighten T, Grade number 0N001, 8 mm thickness that is soldby the company EVONIK Industries. The refractive index of this PMMA is1.491 measured using ISO 489. According to another embodiment, theorganic glass layer embeds particles only on a part of its volume, forinstance only in a central part of that substrate. The CTE of the PMMAis comprised between 70 and 77.10⁻6/K⁻¹ Different particleconcentrations can be used and can be adapted to the dimensions of theglass panel 1.

In case the intermediate organic glass substrate 105 is PMMA, the secondprofile is preferably made from PMMA material in order to have the sameCTE.

The glass of the first and second glass substrates can be coated,tinted, tempered or bended or a combination of these.

Then, thanks to the presence of the diffuser particles in theintermediate organic glass substrate 105, the organic glass substrate105 cause the light emitted by the light sources (LEDs 106) to diffuseforward and then deflects the light emitted by the LEDs 106 out of theplane of the panel 1 and through the first and second glass substratesto provide a diffused light output.

Basic methods for assembling/manufacturing glass, without the novelfeatures of the present invention, for use in this and other embodimentsare well-known in the window/double glazing industry.

According to a present particular embodiment, a method of manufacturingof the glass lighting panel 1 comprising the first glass substrate 101and the second glass substrate 102, is illustrated on FIG. 2 andcomprises the following steps:

-   -   providing 301 the spacer profile 103 at the periphery of the        glass panel between the first and the second glass substrate to        maintain the intermediate space 104 between the first and second        glass substrates,    -   providing 302 the second profile 100 positioned facing the inner        face of the spacer profile 103 within the intermediate space        between the first 101 and second 102 glass substrates of the        glass panel, the second spacer having the same coefficient of        thermal expansion than the coefficient of thermal expansion of        the intermediate substrate,    -   maintaining 303, thanks to the second profile, an intermediate        organic glass substrate 105 in the intermediate space between        the first and the second glass substrates,    -   lodging 304, thanks to the second profile, the LEDs 106 so as        they emit light into the intermediate organic glass substrate        predominantly along a plane of the panel,    -   arranging 305 at least part of the intermediate organic glass        substrate 105 to deflect the light out of the plane of the panel        and through at least one of the first and second glass        substrates to provide a diffused light output.

In some cases one or both the first and second glass substrates can beflat soda lime glass, notably float glass. One or both of the first andsecond glass substrates may be clear glass, extra clear glass or bodytinted glass. Particularly when intended for use in window applications,the glazing panel may be substantially transparent. In this case, it mayhave a light transmission (CIE Illuminant C) of greater than or equal to40%, 50%, 60% or 70% and/or a level of haze of less than or equally to5%, 3% or 2% for example. Particularly when intended for decorationand/or lighting purposes, it may be unnecessary and/or undesired for thepanel to be substantially transparent. In this case, it may have a lighttransmission (CIE Illuminant C) of less than or equal to 20%, 10%, or 5%and/or a level of haze of greater than or equally to 30%, 40% or 50%.

Examples of additives to make the organic glass layer diffusive canencompass inorganic particles of glass, silica, mica, synthetic mica,calcium carbonate, barium sulfate, talc, montmorillonite, kaolin clay,bentonite, hectorite, etc., metal oxide particles of titanium oxide,zinc oxide, tin oxide, alumina, etc., or organic polymer particles ofacrylic beads, styrene beads, benzoguanamine, silicone, etc.

More diffusion can be obtained by surface roughening of a light-emittingface accomplished by cutting using a saw or an automatic cutter (forexample, an NC router) or by blasting, surface grinding using a grinder,emboss forming, etc. In the case of blasting, particles are appliedusing a high-speed blasting machine over the surface of the organicglass layer, the interlayers or the glass substrates to form randomprojections and depressions, and the thus formed surface can be used asthe light-emitting face. In the case of grinding, a grinder using, forexample, a file is used to grind the surface.

The light sources can be colored, and optionally arranged so that thereis color mixing to achieve a uniform white. The relative levels of thecolors can be controlled to control the color temperature if desired.The light sources can also emit in the ultraviolet or infrared spectrum.The panels can be incorporated into buildings, windows, mirrors,backlights for display systems and so on. Arrays of the panels can bebuilt up to illuminate larger areas.

Other variations can be envisaged within the scope of the claims.

1: A glass panel, comprising: a first glass substrate; a second glasssubstrate; a spacer profile at a periphery of the glass panel betweenthe first and the second glass substrate, the spacer being used tomaintain an intermediate space between the first and second glasssubstrates, the spacer profile having an outer surface and an innersurface; an intermediate substrate in the intermediate space between thefirst and the second glass substrates, having a first coefficient ofthermal expansion; means (108) to maintain the intermediate substratewithin the intermediate space. a second profile, having a secondcoefficient of thermal expansion, positioned facing the inner surface ofthe spacer profile within the intermediate space between the first andsecond glass substrates of the glass panel, wherein the second profilecarries the means to maintain the intermediate substrate within theintermediate space, and wherein a difference between the firstcoefficient of thermal expansion of the intermediate substrate and thesecond coefficient of thermal expansion of the second profile is lessthan or equal to 20%. 2: The glass panel according to claim 1, whereinthe means to maintain the intermediate substrate within the intermediatespace comprises: at least one first opening in an upper portion of thesecond profile, at least one second opening in a lower portion of thesecond profile, the first and the second openings being disposed inregard, the at least first and second openings being designed to lodgeat least a portion of edges of the intermediate substrate. 3: The glasspanel according to claim 1, wherein the panel is disposed in a verticalposition and the means to maintain the intermediate substrate comprisesmeans to attach an upper portion of the intermediate substrate to anupper portion of the second profile and/or to attach a bottom portion ofthe intermediate substrate to an upper portion of the second profile. 4:The glass panel of claim 1, wherein the intermediate substrate ispreferably fixed to the internal faces of the first and second openingsprovided in the second spacer profile. 5: The glass panel of claim 2,wherein the at least a portion of the edges (upper and lower) of theintermediate substrate is inserted into corresponding first and secondopenings and glued to internal faces of the first and second openings.6: The glass panel of claim 1, wherein the second spacer has a samecoefficient of thermal expansion as the intermediate substrate. 7: Theglass panel of claim 1, wherein the second profile and the intermediatesubstrate are made of Poly(methyl methacrylate) material. 8: A lightingpanel comprising the glass panel of claim 1, further comprising: atleast one light source, wherein the intermediate substrate is anintermediate organic glass substrate, wherein the second profile furthercomprises means to lodge the at least one light source so as the atleast one light source emits light into the intermediate organic glasssubstrate predominantly along a plane of the lighting panel, and in thatat least part of the intermediate organic glass substrate is arranged todeflect the light out of the plane of the lighting panel and through atleast one of the first and second glass substrates to provide a diffusedlight output. 9: The lighting panel of claim 8, wherein the means tolodge at least one light source is a profile embedded into the secondprofile between the first and the second glass substrates so as to facean edge of the intermediate organic glass substrate. 10: The lightingpanel of claim 8, wherein the means to maintain the intermediatesubstrate within the intermediate space has a inversed U-shape profileand is made from a metallic material. 11: The lighting panel of claim 8,wherein the means comprises at least a housing being arranged betweenthe first and the second openings so as to face an edge of theintermediate organic glass substrate. 12: The lighting panel of claim 8,wherein the intermediate organic glass substrate is at least partiallylight diffusive to cause the light to be deflected. 13: The lightingpanel of claim 8, wherein the intermediate organic glass substrate is aPoly(methyl methacrylate) layer. 14: The lighting panel of claim 13,wherein the intermediate organic glass substrate is a Poly(methylmethacrylate) layer embedding colorless diffuser particles which causethe light to diffuse forwards. 15: The lighting panel of claim 14,wherein the intermediate organic glass substrate and the second profileare made of Poly(methyl methacrylate) material.